MOORE, Okla. - Viewers glued to TV following Monday's tornado that hit here with the destructive force of an atomic bomb very likely expected to wake up Tuesday to a death and injury toll in the thousands.

How could anyone have survived the apocalyptic destruction of a worst-of-the-worst EF5 category storm? Miraculously, most did, despite an official warning coming just 16 minutes before the twister cut a 17-mile war-zone-like path through this city of 56,000.

Local, state and federal officials credit luck, happenstance, timing, faith, heroics, preparation and the seasoned experience that comes with living in the heart of Tornado Alley for the relatively low victim count.

"If they say there's a chance of severe tornadoes, people take it really seriously," said Tyler Porter, who lives in Oklahoma City, 10 miles north of Moore. "They pretty much know when it's time to take cover."

The death toll stands at 24 - revised from an initial 51 - plus 237 injured. Late Tuesday, about 200 rescue workers were rechecking scores of homes, businesses and schools already marked by a bright orange security "X" a second and third time. But by late afternoon, Moore City Fire Chief Gary Bird said he was "98% sure" there were no more victims or survivors to recover.

"This was a ferocious monster. When I saw it on TV, I thought (victims) could easily be in the triple digits," said Rep. Tom Cole, a Republican congressman who was raised in Moore and has represented the district since 2003.

Meteorlogists contacted by the Associated Press used real-time measurements to calculate the energy released during the storm's life span of almost an hour. Their estimates ranged from eight times to more than 600 times the power of the Hiroshima bomb.

But Cole, 64, said the people in his district were hardened and battled-tested from previous twisters.

"We've gone through this four times in the past 15 years," he said Tuesday evening after arriving in Oklahoma and surveying the damage. "People may only have minutes, but there is nothing else on radio or TV when these things are coming. People know to move toward shelter or literally get in their cars and drive away."

FRESH FEARS FROM 1999

To be sure, the latest tornado - just one of only 58 EF5s to hit the USA since the early 1950s - was 40 minutes of sheer terror followed by long hours of numbing shock. Damages could exceed $2 billion, making it one of the most destructive twisters ever. About 20,000 residents have been displaced. But countless lives were likely saved because "people took the necessary precautions," says J. Marshall Shepherd, a research meteorologist at the University of Georgia.

Porter's wife, Mandy, grew up here and remembers the horrific twister that ravaged the area in 1999, influencing how many residents rebuilt and respond to storm warnings. That EF5 storm, with wind speeds at more than 300 mph, killed 36 while carving a 41-mile path through the region. Many families now have a safe rooms in their garages or tornado-proof shelters underground or bolted to concrete pads.

As Monday's tornado bore down "sounding like a diesel engine truck," Porter says, he hunkered down at his in-laws' home instead of their third-story apartment. Mandy Porter rode out the storm at Red Oak Elementary, where she is a substitute teacher.

The school notified parents of severe weather warnings about an hour before the tornado hit. Some parents managed to get their kids. With the tornado closing in, teachers gathered remaining children in an administration building hallway, he said. "They did the best they could. They don't have a safe room," Porter said.

No one at Red Oak was injured. Moore's Plaza Towers Elementary wasn't as fortunate.

Seven students - nearly one-third of Monday's known fatalities - were killed after the school's roof was ripped off and walls crumbled. First responders managed to pull out several other students from a collapsed wall and heaps of mangled debris, passing survivors down a chain of parents and volunteers. Congressman Cole, who used to work as a groundskeeper in his youth near the school, said Plaza Towers was directly in the path of the tornado.

'TEACHERS STARTED SCREAMING'

Students had been instructed to go to the cafeteria and wait for their parents to pick them up, but then the tornado alarm sounded.

"All the teachers started screaming into the room and saying, 'Get into the hallway! We don't want you to die!' and stuff like that," said sixth-grader Phaedra Dunn. "We just took off running."

Sixth-grader Antonio Clark said a teacher shoved him and others into the three-stall boys' bathroom.

"We were all piled in on each other," the 12-year-old said. Another teacher wrapped her arms around two students and held Antonio's hand.

Twenty seconds later he heard a roar that sounded like a stampede of elephants. It stopped almost as suddenly as it started. Crouched down, his backpack over his head, Antonio looked up. The skylight and the ceiling were gone, and he was staring up into a cloud filled with debris.

Antonio and a friend were among the first to stand. They climbed over debris where their classroom had been just moments earlier. Students and teachers were struggling to free themselves from the debris. Some had bleeding head wounds; blood covered one side of someone's eyeglasses, Antonio said.

"Teachers and administrators made the right decision," Cole said of Plaza Towers' staff. "It's the safest building in that neighborhood. Not many structures above ground can stand up to that kind of tornado."

Claudia Todd, past president of the district Parent Teacher Association in Moore, said most local schools conduct extreme storm drills at least once a month. Students practice filing into interior classrooms, and incoming high school freshman are sent home with books that carefully explain drills.

"You take those precautions seriously, especially in Oklahoma," said Todd, a secretary at Southmoore High School.

After the 1999 tornado, drills were practiced with more intensity. "When you hear those warnings, you don't just go, 'It's just another warning,'" Todd said. "You take them seriously."

Other survivors emerged from homes with harrowing accounts of the storm's wrath as they shielded loved ones.

Chelsie McCumber grabbed her 2-year-old son, Ethan, wrapped him in jackets and covered him with a mattress before they squeezed into a coat closet. She sang to Ethan when he complained it was hot inside the small space.

"I told him we're going to play tent in the closet," she said, beginning to cry. "I just felt air so I knew the roof was gone," she said Tuesday, standing under where her roof should have been. The home was littered with wet, gray insulation and family belongings.

SHELTERS MADE THE DIFFERENCE

Tornado shelters helped save others. As the twister approached, Jalayne Jann dashed into the underground concrete shelter she installed after the 1999 tornado decimated her brother's house. She emerged from the shelter to war-zone-like scene of crushed cars, flattened homes and downed trees.

"We've lived here a long time. We're used to tornadoes," Jann said as she surveyed her ruined home. "But they always go around or over. Nothing ever like this."

Jon Johnson says his 6-year-old daughter, Abigail, and his mother-in-law escaped harm by waiting out the storm in an underground concrete bunker in the back yard of his home, which is now a mangled pile of bricks, wood studs and sheet rock.

"That saved their lives," he said. "If they were above ground, they wouldn't have made it."

The bunker was there when he bought the home in 2001. "If you live in Oklahoma, you have to have one of these," said Johnson, 44.

Four Oklahoma City residents were killed by the tornado. But Mayor Mick Cornett said the death toll may have been tempered by the timing of the storm. Many area residents were still at work or reinforced school buildings when it the tornado hit.

Cornett also credited the news media. "This was the storm of storms," he said. "The fact that so many lives have been saved is a testimony to the technology of media. No doubt, the media saved hundreds of lives."